The present invention relates to shifters for transmissions of passenger vehicles, and more particularly relates to shifters having devices to control movement of the shift lever between gear positions.
Passenger vehicles in the United States have the driver's seat positioned in a front left side of the passenger compartment. The transmission shifter is typically positioned between the front vehicle seats for operation with the driver's right hand. However, passenger vehicles in many other countries, such as Japan, position the driver on the front right side of the passenger compartment. The shifter is often still positioned between the vehicle seats, but the shifter is located on a left side of the driver for left-handed operation. This can cause numerous problems in factories created to manufacture both left-hand drive and right-hand drive vehicles. For example, twice as many part numbers are created, one set for right-hand driven vehicles and one set for left-hand driven vehicles. Inventories increase dramatically because there are twice as many parts that must be inventoried. Further, twice as many tools and fixtures must be created and lower volumes of each parts are used, thus reducing efficiencies of manufacture while adding to storage costs. Also, there are significant advantages to postponing the decision as to which type vehicle (i.e., left-hand or right-hand drive) will be produced to as late in the assembly process. Further, there are advantages to being able to switch a vehicle from left-hand to right-hand style and vice versa with as few parts as possible. Thus, a shifter that uses a maximum of common parts is desired.
Modern vehicle shifters also have another problem. Modern vehicle shifters have park lock devices that lock their shift levers in the park gear position until predetermined vehicle conditions are met. For example, federal regulations require that a vehicle's brake pedal be depressed and an ignition key be turned on before a shift lever can be moved from its park gear position to a drive gear position. The reason for this is so that the vehicle is operational but braked before an operator shifts into gear. Also, modern vehicle shifters are now being specified or proposed with neutral lock devices and/or reverse lockout devices to prevent them from being accidentally shifted from drive gear position or neutral gear position into reverse gear position while the vehicle is moving forward at too great of speed. Some shifter systems are proposed that are constructed to prevent a transmission from shifting from drive gear position into reverse gear position while the vehicle is going too fast, but they typically do not prevent the shift lever itself from being accidentally moved into the reverse gear position. As a result, when the vehicle does slow down and the transmission is "unlocked," the transmission drops with a sharp jolt into the reverse gear position. This can result in a potentially unsafe condition since the vehicle suddenly and unexpectedly operate. It is desirable to prevent the shift lever itself from being accidentally shifted from the drive gear position into the reverse gear position.
Several ways are known to provide a park lock. Often they use a solenoid to extend a pin into a pawl-engaging cam in a way that prevents a pawl from exiting a park notch. The solenoid is connected to a control circuit with a controller programmed to require that predetermined vehicle conditions be met before the solenoid is energized. As a result, a shift lever cannot be moved out of its park gear position until the predetermined vehicle conditions are met. For example, the predetermined vehicle conditions may include a requirement that the brake pedal be depressed.
Present proposals for neutral lock devices include a second solenoid not unlike the park lock solenoid. This second solenoid has an extendable pin that can be extended to engage a pawl-engaging cam in a way that prevents the pawl from moving from neutral toward the reverse or drive gear position unless predetermined vehicle conditions are met. A problem is that solenoids are expensive, and including two solenoids in a shifter results in a relatively expensive shifter assembly.
Some park lock devices utilize a cable connected to a vehicle component, such as to a brake pedal or actuator. The cable is connected to the shifter in a manner preventing shifting from park gear position until predetermined vehicle conditions, such as the ignition key being on, are met. However, cables are also expensive to purchase. Further, the cables must be routed in the vehicle and connected at each end, making them expensive to install. Further, it is not at all clear how such a construction could be made to provide a neutral lock function.
Accordingly, a shifter solving the aforementioned problems and having the aforementioned advantages is desired.